1. Field of the Invention
Natural rubber is a raw material vital to our commercial and defense needs, and many consumer products are made with natural rubber obtained from Hevea brasiliensis (Hevea) species. The high-performance characteristics of natural rubber cannot be simulated by any other known material. These characteristics include high elasticity, resilience and low heat build-up.
Any of these products, however, can cause severe allergic reactions in hypersensitive individuals. The occurrence of "rubber allergy" first appeared in-the late 1980's and is now widespread; more than half a million Americans may be affected. Health care professionals who routinely wear rubber gloves and patients who undergo multiple surgeries, such as children with spina bifida, are particularly susceptible to sensitization. As no equivalent non-rubber replacement materials are currently available, there is a need to provide alternative sources for the manufacture of rubber products which are non-allergenic. This invention relates to the preparation of non-allergenic rubber products from alternative sources of rubber which do not cause allergic reactions due to "rubber allergy".
2. Description of the Prior Art
Allergic reactions to Hevea rubber products can be severe, and are caused by proteins present in the rubber-containing latex. Review articles have been published addressing the issue of allergic reactions to natural rubber by both health care workers and patients as a result of an increase in the use of disposable latex gloves and other rubber medical devices (Maso and Goldberg, Journal of the American Academy of Dermatology, v. 23, pp. 733-737, 1990; Slater, J. E., Annals of Allergy, v. 68(3), pp. 203-209, March, 1992; Tomazic et al., Clinical Immunology and Immunopathology, v. 64(2), pp. 89-97, August, 1992). Allergic reactions range from an itchy, burning rash to anaphylactic shock. In addition, conditions such as dermatitis, pruritus, urticaria and swelling of the hands, edema of the arms, trunk, face and/or eyelids, laryngeal edema and eyelid dermatitis in the absence of hand eczema may appear. The occurrence of rhinitis, conjunctivitis, coughing, sneezing, asthma, dyspnea, palpitations and dizziness have also been reported. Although exposure to latex gloves is considered responsible for the most of the reported allergic reactions, other rubber medical products, such as catheters, dental devices, condoms, anesthesia masks and barium enema kits, and non-medical products, such as balloons and children's toys, are also implicated in inducing hypersensitivity reactions.
Proteins associated with natural rubber are generally accepted as the primary cause of latex sensitivity, and protein content may vary according to source, lot and manufacturing process. Both type I (immediate, IgE mediated) and type IV (delayed) immune responses have been reported, prompting the FDA to issue a medical bulletin as well as a medical alert regarding possible severe systemic reactions to latex-containing medical devices. To date, the avoidance of use by high risk patients and changes in the manufacturing process are the major approaches to the management of rubber hypersensitivity. The only alternative materials suggested are synthetic materials such as polyurethane and polyvinyl chloride. These materials also carry risks of inducing sensitivity, however, and do not have the high-performance characteristics which make natural rubber products so attractive. As yet, no natural alternative source has been discovered which provides the necessary safety factors for these products which are so widely utilized. Therefore, the search for an effective alternative has continued.